Russian Journal of Genetics 40(9): 995-1002 (Sept 2004)
Polymorphism and Inheritance of Seed Storage Protein in Sunflower
I. N. Anisimova1, V. A. Gavrilova1, A. V. Loskutov2, V. T. Rozhkova1  and V. V. Tolmachev2
(1) Vavilov Institute for Plant Industry (VIR), St. Petersburg, 190000, Russia
(2) Pustovoit All-Russia Research Institute of Oil-Bearing Cultures, Krasnodar, 350038, Russia

Abstract The data on polymorphism and inheritance of the seed storage protein helianthinin are presented. The results of hybrid analysis indicate that in the annual sunflower Helianthus annuus, helianthinin synthesis is controlled by at least three loci: HelA, HelB, and HelC. Codominant alleles controlling different electrophoretic variants of polypeptides were identified at each of the loci. The HelA locus was inherited independently of HelB and HelC in a series of dihybrid crosses. The frequencies of recombination between loci HelB and HelC estimated in F2 and BC of two crossing combinations were respectively 21.8 and 19.0%. Segregation of the HelC-controlled variants in the progenies from the crosses of cultured sunflower with annual wild species and forms corresponded to that theoretically expected for Mendelian inheritance. The maternal type of helianthinin inheritance was observed in the progenies from the crosses of inbred H. annuus L. lines with perennial diploid and polyploid Helianthus L. species. Altered expression of the HelC locus was detected in some hybrid combinations. These alterations appeared in early (F1, F2) hybrid generations and were similar in different hybrid combinations. They did not depend on the perennial paternal species being more influenced by the maternal genotype and by the mode of obtaining hybrids (in an embryo culture or in the field). These results are explained by genomic shock generated by hybridization of genetically incompatible species.

The data on the inheritance of the polypeptide composition of a seed storage protein upon hybridization of H. annuus with perennial species from the genus Helianthus were obtained for the first time in the present study. The observed facts, in particular, the change in the expression of the same locus (HelC) irrespective of the genotypes of the hybridizing forms, can be explained by the effect of so-called "genomic shock"; (introduction of alien genetic material to a new genetic background) [21]. A screening of the progenies from crossing the cultured sunflower with perennial diploid species H. mollis and H. orgyalis DC using methods RAPD and RFLP showed that only a small portion of the plants carried the genetic material of both parental forms. Most progenies carried only fragments of the genome of the perennial parent, while some fragments were apparently produced by intragenomic and intergenomic rearrangements [22]. Analysis of the interspecific hybrid H. annuus x H. tuberosus yielded similar results [23]. Similarly to the phenotypic changes, the character of molecular alterations were identical in both plants. Natali et al. [23] attributed the genome rearrangement upon interspecific hybridization of sunflower to DNA methylation (demethylation). Apparently, DNA regions differ in the extent of these alterations. In light of the above evidence, the observed changes in the HelC expression may be caused by similar alterations of the same genomic sequences under conditions of genomic shock generated by distant hybridization.